Modified Shoelace Dural Closure with Collagen Matrix in Extended Transsphenoidal Surgery

Histopathological analysis of duragen collagen matrix over time in humans

DuraGen is a widely used type I collagen matrix derived from bovine Achilles tendon that promotes fibroblast ingrowth and neovascularization. However, it remains unknown the time required for dura regeneration and reabsorption of the graft. We evaluate the histopathological characteristics of implanted DuraGen in humans across multiple time points. Patients who underwent a decompressive craniectomy and duraplasty with DuraGen at our institution between January 2020 and September 2021 were prospectively enrolled. At the time of the subsequent surgery, including cranioplasty, DuraGen and associated tissues removed from patients were sent for histopathological analysis. For each patient, time from index surgery to subsequent surgery was categorized into three groups: early (0-20 days), intermediate (21-30 days), and late (> 30 days). Baseline characteristics, primary disease, operative time, complication rate, and histopathological findings were compared between groups. A total of 28 patients were enrolled in the study. Seven specimens (25.0%) were collected within 20 days after craniectomy, 9 specimens (35.7%) between 21 and 30 days, and 12 specimens (39.3%) over 31 days. Histopathologically, implanted collagen matrix, erythrocyte infiltration, and fibrin layer decreased over time, whereas fibroblasts and endogenous collagen increased. Receiver operating characteristic analysis showed that the cut-off time post-implantation for presence of endogenous collagen was 34 days after DuraGen implantation (area under the curve = 0.810). We found that DuraGen was replaced by fibroblast-derived endogenous collagen as early as 34 days post-implantation. Although certain findings remain to be further validated, the present study substantiates DuraGen as a reliable substitute, with findings derived from clinical outcomes and histopathological changes.

A Case of Papillary Craniopharyngioma Mimicking Rathke's Cleft Cyst

Craniopharyngioma (CP) and Rathke's cleft cyst (RCC) are both suprasellar lesions. They are sometimes difficult to distinguish due to their similar findings. We report a case of papillary craniopharyngioma (pCP) with the clinical findings suggesting RCC. A 42-year-old female with intellectual disability presented to our hospital with severe visual dysfunction. Preoperative images revealed a suprasellar cystic lesion without calcification. We performed transsphenoidal surgery. Since the cyst had condensed-milk-like content suggesting RCC, we performed cyst fenestration and wash without removal of the cyst wall. Thereafter, we found fish-egg-like structures on the cyst wall. The histopathological analysis revealed that they had papillary structures surrounded by hyperplastic squamous epithelium with parakeratosis. Immunostaining for BRAF V600E was positive, leading to the diagnosis of pCP. After the surgery, her visual function improved and follow-up Magnetic resonance imaging at 18 months postoperatively showed no apparent recurrence. The presence of condensed-milk-like content suggests a likelihood of RCC indicating that aggressive resection may not be necessary. In contrast, the existence of fish-egg-like structures suggests pCP and requires careful follow-up.

The importance of preserving the superior hypophyseal artery infundibular branch in craniopharyngioma surgery

PURPOSE

Postoperative pituitary dysfunction, a critical problem in the treatment of craniopharyngiomas, can occur even when the pituitary stalk is preserved. We hypothesized that compromise of the primary superior hypophyseal artery (pSHA) might be related to this occurrence.

METHODS

We performed a retrospective review of 131 patients with craniopharyngioma who underwent surgery from April 2009 to September 2021. The inclusion criteria were initial surgery, endoscopic transsphenoidal surgery, preoperative normal pituitary function or pituitary dysfunction in one axis, and morphological preservation of the pituitary stalk. The branches of the pSHA consist mainly of the chiasmatic branches (Cb), infundibular branches (Ib), and descending branches (Db). We analyzed the association between postoperative pituitary function and preservation of these branches.

RESULTS

Twenty patients met the criteria. Preoperative anterior pituitary function was normal in 18 patients, and there was isolated growth hormone deficiency in two patients. No patient had preoperative diabetes insipidus (DI). Anterior pituitary function was unchanged postoperatively in eight patients. Of these eight patients, bilateral preservation of pSHA Ib was confirmed in seven patients. Bilateral preservation of pSHA Ib was the only factor associated with preserved anterior pituitary function (p < 0.01). Fifteen patients were free of permanent DI, and the preservation of any given pSHA branch produced no significant difference in the postoperative occurrence of permanent DI.

CONCLUSIONS

Our study shows that bilateral preservation of pSHA Ib provides favorable postoperative anterior pituitary function in craniopharyngioma surgery; however, such preservation may have little effect on the postoperative occurrence of DI.

Meningioma Cell Invasion into DuraGen-Derived Dura Mater: A Case Report

Background: Dura mater infiltration is the main growth pattern of meningiomas. Local recurrence may occur in any type of meningioma, but it is more likely so in atypical meningiomas. Therefore, a wide resection of tumor cell-invaded dura mater is necessary to avoid recurrence. DuraGen^® (an artificial dural substitute) can be used for dural reconstruction in meningiomas. Here, we report a rare case of a patient with atypical meningioma that invaded into the DuraGen^®-derived mature dura mater. Case presentation: A 66-year-old female showed a three-time recurrence of atypical meningioma. Simpson grade I resection (en bloc tumor with autologous dura mater and DuraGen^®-derived dura mater resection) was achieved at the 3rd recurrence. Collagen fibers running regularly and transversely were observed in the DuraGen^®-derived dura mater resembling the autologous meningeal layer. Meningioma cell invasion, displayed by occasional EMA immunostaining, was observed in the DuraGen^®-derived dura mater. Conclusions: This case indicates that meningioma cells may invade and survive in the DuraGen^®-derived dura mater. Whether or not DuraGen^® is not appropriate as a dural substitute remains unanswered. Further experiences are needed to validate these findings in large sample sizes.